Treating and refining hydrocarbon oils



Nov. 28, 1933. P. KRAU'EL, El AL 1,936,629

TREATING AND REFINING HYDROCARBON OILS Filed June 11, 1931 2 Sheets-Sheet i Nov. 28, 1933. P. 1.. KRAUEL ET AL TREATING AND REFINING HYDROCARBON OILS ,aZ x f d 3% 1, z

Patented Nov. 28, 1933 UNITED STATES PATENT OFFICE Philip L. Krauel and George W. Watts, Whiting, Ind., assignors to Standard Oil Company, Whiting, Ind., a corporation of Indiana Application June 11, 1931. Serial No. 543,700

20 Claims.

The present invention relates to improvements in the refining and treating of hydrocarbon oils, particularly the lighter hydrocarbon oils to effeet the removal of sulfur-containing constituents therefrom and secure products of desired boiling point characteristics. It will be fully understood from the following description, illustrated by the accompanying drawings, wherein:

Figure 1 is a diagrammatic showing of a relatively simple form of apparatus suitable for carrying the invention into effect; and

Fig. 2 is a diagrammatic view of a modified layout of apparatus in which the invention may be carried out.

It has hitherto been customary, in the treatment of light hydrocarbon oils, for example, those in the gasoline and kerosene ranges of boiling points, in order to remove sulfur compounds which produce sourness, to, employ the reagent known as doctor and consisting of an alkaline solution of sodium plumbite in conjunction with elemental sulfur, the latter being effective in the breaking down and removal of soluble sulfur compounds, such as the higher lead mercaptides, which result from the action of the reagent. The use of elemental sulfur or of reagents having a similar action, although the common practice and hitherto regarded as necessary, may and frequently does have undesirable consequences and leave a treated product which does not satisfactorily respond to the analytical tests for freedom from sour sulfur compounds. By operating in accordance with the present invention, the use of free sulfur or equivalent materials in aiding the action of the doctor reagent is rendered entirely unnecessary and furthermore, by properly conducting the operation, the refining of the material treated to the desired boiling point characteristics may, at the same time, be .accomplished.

Referring more particularly to the drawings, in Fig. 1, the light hydrocarbon oil to be subjected to treatment, which may be, for example, the pressure distillate recovered from any pressure cracking operation and containing constituents in the gasoline boiling point range together with higher boiling products may be suppliedv to a continuous mixing device 5 through line 6, the doctor solution of the desired strength and in the desired proportion being supplied to the mixture through the line 7. The mixer 5 may be of any continuously operating type, for example, a baffle or orifice mixer. The mixture pases out through the line 8 to the settling tank 10, in which the doctor sludge is permitted to settle from the oil, together with insoluble, precipitated, compounds resulting from its action. The treated oil, which still contains soluble sulfur compounds, such as the higher lead mercaptides, is withdrawn from the settling tank 0 10 (after suitable washing to remove alkali, if desired) through line 11 by pump 12 and forced through line 13 to a heating device 14, which is preferably a pipe still, or any other desirable type of heating device may be employed.

In passing through the pipe still or other heating device, the oil is heated to a temperature at which decomposition of the dissolved organic lead-sulfur compounds is effected and lead sulfide thrown out, the lead sulfide being carried along with the stream of heated products. Or-

dinarily, with oils of the character described, some vaporization will be effected. Thus, with a typical pressure distillate product, its temperature may be carried to 300 to 350 F. in passage through the pipe still with a resulting vaporization of 25% or higher. With heavier oils, such as naphtha bottoms, burning oil distillates and the like, a lower proportion of vaporization may take place. so

The heated products pass out of the pipe still or other heating'device through the line 15 and are discharged into the enlarged chamber or flash drum 16, in which separation of vapors from the unvaporized products takes place. The unvaporized liquid, which carries with it the insoluble lead sulfide thrown out by the heating of the'oil, passes out of the flash drum 16 through the valved line 1'? to a settling chamber 18, which is preferably of a type to permit of a very substantial reduction in velocity of movement of the liquid and permits the sedimentation or settling of the lead sulfide precipitate. The settling chamber 18 may thus suitably be a substantially horizontally positioned cylindrical drum. In passage through the chamber 18, insoluble materials separate out of the oil, and the clear oil is discharged through the line 19 into the fractionating tower 20 at an intermediate point thereof. w

The vapors which separate in the enlarged chamber or flash drum 16 pass out through the vapor line 21 and likewise enter the fractionating column 20 at an intermediate point, above the point at which the liquid constituents of the 105 oil are admitted.

The fractionating column 20 contains fractionating plates of any suitable type, and heat is applied to the lower portion of the column in any suitable manner, for example, by the pas- 110 sage of a heating medium through the coil 22 in the liquid contained in the lower portion of the column. Reflux may be provided in the column by the application of a cooling medium in the upper portion thereof, for example, by caus it to flow through the coil 23. The supply of heat to the heating coil 22 and of cooling medium to the cooling coil 23 are so controlled as to cause to pass overhead through the vapor line 24 to suitable condensers and collectors (not shown) a light fraction or distillate and to remove, from the drawout line 25 at the bottom of the column, a heavy fraction, one or the other, or both having specified boiling point characteristics. Thus, the operation may be so conducted, with one type of oil under treatment, as to produce as an overhead through the line 24 a motor fuel distillate having an end point of, say, 396 or 400 F.; or with a heavier oil under treatment, the operation may be so conducted as to remove, through the drawout line 25, as a heavy fraction, a furnace oil or illuminating oil of a desired flash point.

In Fig. 2 is illustrated a modified form of apparatus particularly adapted for the treatment and refining of a stock such as pressure still distillate. In the operation according to this modiflcation of the process, the pressure still distillate which has been treated with doctor solution in the absence of free-sulfur and separated from the doctor sludge, and therefore contains leadsulfur organic compounds in solution, is supplied by a pump or under pressure through line 30 to coil 31 in the upper portion of the fractionating column 32, which corresponds in many respects to the column 20 of the form shown in Fig. l. The oil passes through the coil 31, acting as a cooling medium and being somewhat preheated, and after leaving the coil 31 passes through the line 31 to the coil 33, positioned at a lower point in the column, at which point it exercises a further cooling action and iscorrespondingly furtheipreheated. The oil, which has at this time attained a temperature of, say, 320 to 330 R,

passes through line 34 to and through a heat exchanger 36, in which it is further preheated by heat exchange with a heavy fraction removed from the column 32 as hereinafter described, said heavy fraction being one suitable for use asfurnace oil. From the heat exchanger 36 the oil leaves the heat exchanger through the line 37, passing through a heat exchanger 39, in

which it is further heated by a heavier fraction removed from the column 32, through line 70.

The oil, now preheated to some extent, even to a temperature at which some decomposition of the lead-sulfur organic compounds occurs say 325 F. or above, passes out of the heat exchanger 39 through line 40 to pipe still 41, diagrammatically shown. In the pipe still 41, the oilis further heated to a temperature sufllcient to effect further decomposition of the lead-sulfur organic place, the effectiveness of separation being aided by providing in the upper portion of the drum a plurality of baiiie plates 44 and supplying to the upper portion of the drum a low boiling condensate collected and removed from the fractionating tower through line 45, by which it is conducted which the insoluble lead-sulfide is separated out.

The liquid, free from precipitated lead-sulfide, passes out of the settling drum 48 through the line 49 and is discharged into the column 32-at an intermediate point near its bottom.

A desired temperature, which may be, for example, 425 to 456 F. or even higher, is maintained in the liquid in the base of the fractionating column 32 by withdrawing a portion of the liquid through the line 50, forcing it by pump 51 through a line 52 to and through a suitable heating device 53, which may, for example, be a pipe still furnace, and returning it to the lower portion of the fractionating column. Instead of returning it directly, it is preferred that it pass from the heating device or pipe still furnace 53 through line 54 to and through a coil 55 in a stripping column 56, to which a heavy fraction, for example, a furnace oil fraction, trapped out of column 32 is supplied through the line 57. The heated heavier oil passing through the coil 55 effects some increase in temperature of the oil supplied to the column 56 and removes the lighter fractions therefrom, these returning to the column through the vent line 58. The oil which is passed through the coil 55 then returns to the column through the line 59 at a temperature which will maintain the desired temperature in the body of liquid in the lower portion of the column.

In the operation of the column 32, the top of the column is held at a temperature such that the light products desired in motor fuel together with incondensible gas will pass out through the vapor line 60 to suitable condensers and separators (not shown). For this purpose, the temperature at the top of the, column may suitably be maintained at 250 to 300 F., say about 275 F. This temperature may be maintained in whole or in part by the cooling medium passed through the coil 31, which may be aided by the return of the distillate product recovered by condensation from the vapors passing out through the line 60, this distillate being returned through the line 61, in the upper portion of the column.

Intermediate condensates suitable for various uses may be withdrawn at various intermediate points of the column. For example, a heavy naphtha condensate produced and collected in the column may be withdrawn through the line 62. This condensate may be secured at the point in the column at which the temperature therein is, say 320 to 330 F. At a lower point in the column, a heavier reflux condensate suitable for use as a furnace oil stock may be withdrawn, as through the line 57. In order that this condensate may be freed of light ends and rendered suitable for t use as a furnace oil or for other purposes, it may be discharged into the heating column 56, in which it is heated by the stream of oil removed from the bottom of the column and passed through the heating device 53 as hereinbefore described. This heated oil passes through the coil 55 in the stripping column 56, thereby raising the temperature of the oil stock supplied thereto, and any vapors of lighter constituents driven off therefrom pass out of the heating column 56 through the vent line 58 and return to the column 32 at a point somewhat above the point of withdrawal of the heavy reflux condensate through the line 57. The heated condensate oil from the stripping column 56 is removed from the latter through the line 63 and passes into the heat exchanger 36, hereinbefore referred to, which contains the tubes 35 through which the stock fed to the system may be passed for preheating, as described above. The heavy furnace oil condensate is thereby cooled and is withdrawn through the line 64. The heat exchanger 36 is likewise provided with a vent line 65, which leads to the upper portion of the heating column 56, so that any vapors or uncondensed gases liberated in the heat exchanger 36 may pass, with vapors from the heating column 56, through the vent line 58 back to the column 32.

The heavy or residual fraction produced in column 32 is withdrawn through line '70 and is passed to heat exchanger 39. The heat exchanger 39 is provided with a vent line 66 for the return of liberated gases and vapors to the column 32, and the remaining liquid from column 32 is withdrawn therefrom through valved line '71.

Heat exchanger 39, stripping column 56 and column 32 may be provided with steam lines 67, 68 and 69 respectively to efiect stripping of liquid therein.

Although the heating device 53 has been shown as a unit separate from the heating device 41, it will be apparent that the heating. coils or other heating elements of these devices may be arranged in a single furnace.

We claim:

1. In the treating of light hydrocarbon oils, subjecting the oil to an action of a sodium plumbite solution under conditions to leave dissolved organic lead-sulfur compounds in the oil, heating the oil to decompose said dissolved compounds and form insoluble lead sulfide, while simultaneously vaporizing a portion of the oil, separating the vaporized portion of the oil from the unvaporized portion, separating the insoluble lead sulfide from the latter, and recombining the unvaporized portion of the oil with the vaporized portion.

2. In the refining of light hydrocarbon oils, the method which comprises subjecting the oil to the action of a sodium plumbite solution under conditions to leave dissolved organic lead-sulfur compounds in the oil, heating the oil to a temperature to decompose said dissolved compounds, thereby simultaneously vaporizing a portion of the oil, the lead compounds being decomposed with the formation of insoluble lead sulfide, separating the vaporized portion of the oil from the unvaporized portion, separating the insoluble material from the unvaporized oil, and discharging the unvaporized oil together with the vaporized portion of the oil into a fractionating column for fractionation therein.

3. In the refining of light hydrocarbon oils, the method which comprises subjecting the oil to the action of a doctor solution in the absence of sulfur, whereby soluble organic lead-sulfur compounds are retained in the oil, heating the oil containing such compounds to a temperature to decompose them with the formation of insoluble lead sulfide, thereby simultaneously vaporizing a portion of the oil, separating the vaporized portion from the unvaporized portion, and removing the insoluble lead'sulfide from the oil before fractionating the oil.

4. In the refining of light hydrocarbon oils, the method which comprises subjecting the oil to the action of a sodium plumbite solution in the absence of sulfur, whereby soluble organic leadsulfur compounds are retained in the oil, heating the oil to decompose said dissolved compounds and form insoluble lead sulfide, while simultaneously vaporizing a part of the oil, separting the vaporized from the unvaporized portion of the oil, separating the insoluble lead sulfide from the latter, and recombining the unvaporized portion of the oil with the vaporized portion.

5. In the art of treating light hydrocarbon oils, the method which comprises subjecting such oils to treatment with a sodium plumbite solution under conditions forming soluble organic leadsulfur compounds which remain in the oil, heating the oil while flowing in a restricted stream to eifect decomposition of said compounds while retaining the resulting insoluble lead sulfide in suspension and partially vaporizing the oil, discharging the heated oil products into an enlarged chamber wherein separation of vapors from unvaporized products takes place, removing insoluble compounds from the unvaporized products and subsequently recombining the unvaporized oil with the vapors.

6. In the art of treating light hydrocarbon oils, the method which comprises subjecting such oils to treatment with a sodium plumbite solution under conditions forming soluble organic lead-sulfur compounds which remain in the oil, heating the oil while flowing in a restricted stream to effect decomposition of said compounds while retaining the resulting insoluble leadsulfide in suspension and partially vaporizing the oil, separating the vaporized portion of the oil from the unvaporized portion, discharging the unvaporized products into a chamber wherein sedimentation of the insoluble lead sulfide takes place, separating the oil constituents from the insoluble lead sulfide, and recombining the former with the vapors.

7. In the art of treating low boiling hyd ocarbon oils, the method which comprises heating a sodium plumbite-treated distillate oil containing dissolved organic lead-sulfur compounds, thereby decomposing such compounds with separation of insoluble lead sulfide and vaporizing a portion of the oil, separating the vaporized portion of the oil from the unvaporized portion, passing the vapors into a fractionating column, settling the insoluble compounds from the unvaporized oil, and passing the oil into said fractionating column, whereby constituents of said oil and said vapors are recombined, and supplying heat in the lower portion of said column to secure fractionation therein.

8. In the art of treating low boiling hydrocarbon oils, the method which comprises heating an alkali plumbite-treated distillate oil containing dissolved organic lead-sulfur compounds, thereby decomposing such compounds with separation of insoluble lead sulfide and vaporizing a portion of the oil, separating the vaporized portion of the oil from the unvaporized portion, passing the vapors into a fractionating column, settling the insoluble compounds from the unvaporized oil, and passing the oil into said fractionating colurrm, whereby constituents of said oil and said vapors are" recombined, collecting oil in the lower portion of said column, withdrawthereby decomposing such compounds with sep aration of insoluble lead sulflde and vaporizing a portion of the oil, separating the vaporized portion of the oil from the unvaporized portion,

passing the vapors into a iractionating cclumn,-

removing the insoluble compounds from the unvaporized oil and passing the oil into said fractionating column, whereby constituents of said oil and said vapors are recombined, collecting a reflux condensate in said column and withdrawing it therefrom, collecting unvaporized liquid at a lower point in the column, removing a portion thereof, heating it and passing it in indirect heat conductive contact with the withdrawn reflux condensate, thereby removing lighter constituents from the latter, returning said lighter constituents to the column, and also returning the said unvaporized liquid to the column to supply additional heat therein for fractionation.

10. In the art of refining low boiling hydrocarbon oils, heating the oil and discharging the heated oil products into a fractionating column, cooling the upper portion of the column to provide reflux therein, withdrawing a heavy reflux condensate from an intermediate point in the column, withdrawing unvaporized oil from a lower point in the column, heating said unvaporized oil, bringing it into indirect heat conductive contact with the heavy reflux condensate, thereby vaporizing light constituents of the latter, returning vapors of said light constituents to the fractionating column, and then passing the said heated oil into the fractionating column in the lower portion thereof to supply heat for fractionation.

11. In the art of refining low boiling hydrocarbon oils, heating the oil and discharging the heated oil products .into a fractionating column, cooling the upper portion of the column to pro vide reflux therein, withdrawing a heavy reflux condensate from an intermediate point in the column, withdrawing unvaporized oil from a lower point in the column, heating said unvaporized oil, bringing it into indirect heat conductive contact with the heavy reflux condensate, thereby removing light constituents'from the latter, and then passing the said heated oil into the fractionating column in the lower portion thereof to supply heat for fractionation.

12. In the art of refining low boiling hydrocarbon oils, heating the oil, thereby partially vaporizing it, discharging 'the resulting vapors and unvaporized oil separately into a fractionating column, cooling the upper portion of the column to provide reflux therein, withdrawing a heavy reflux condensate from an intermediate point in the column, withdrawing unvaporized oil from a lower point in the column, heating said unvaporized oil, bringing it into indirect heat conductive contact with the heavy reflux condensate, thereby removing light constituents from the latter, and then passing the said heated oil into the fractionating columnin the lower portion thereof to supply heat for fractionation.

13. In apparatus for the treating and refining of low boiling hydrocarbon oils, a heating means, means for supplying an oil containing organic lead-sulfur compounds in solution to said heating the column, means for collecting and withdrawof lighter constituents from the latter, and means means for heating Lhejoil to decompose the organic lead-sulfur compounds and form insoluble lead sulfide, means for separating vapors resulting from said heating, means for removing the precipitated lead sulfide from the unvaporized oil, and means for combining the unvaporized oil with said vapors.

14. In apparatus for the treating and reflning of low boiling hydrocarbon oils, means for supplying an oil containing organic lead-sulfur compounds in solution, means for heating the oil to decompose the organic lead-sulfur compounds and form insoluble lead sulfide, means for separating vapors resulting from said heating, means for removing the precipitated lead-sulfide from the unvaporized oil, a fractionating column, and means for supplying the separated vapors and the unvaporized oil to said fractionating column.

15. In refining apparatus, a fractionating column, means for heating a light hydrocarbon oil and supplying the heated oil products into said column, cooling means in the upper portion of said column for supplying reflux therein, means for withdrawing a heavy reflux condensate from ing unvaporized oil from a lower point in said column, means for heating the withdrawn oil and for bringing it into indirectheat conductive contact with the reflux condensate to effect removal for subsequently returning the heated withdrawn oil to the column to supply heattherein.

16. In refining apparatus, a fractionating column, means for heating a light hydrocarbon oil and supplying the heated oil products into said column, cooling means in the upper portion of said column for supplying reflux therein, means for withdrawing a heavy reflux condensate from the column, means for collecting and withdrawing unvaporized oil from a lower point in said column, means for heating the withdrawn oil and for bringing it into indirect heat conductive contact with the reflux condensate to effect removal of lighter constituents from the latter, means for returning the vaporized lighter constituents of the heavy reflux condensate to the column, and means for subsequently'returning the heated withdrawn oil to the column to supply heat therein.

17. In apparatus for refining hydrocarbon oils, a fractionating column, means for heating light hydrocarbon oil and passing the heated oil into said column, means for cooling the upper portion of said column, thereby supplying reflux therein, means for collecting and removing heavy reflux condensate from said column, a heating chamber into which said reflux condensate is discharged, means for collecting and removing heavier unvaporized oil from a lower point in. said column, means for heating said unvaporized oil, a coil in the heating chamber, means for passing the saidheated oil through said coil, whereby it is caused to heat the heavy reflux condensate therein, and means for passing the said heated oil from said coil into the fractionating column.

18. In apparatus for refining hydrocarbon oils,

a fractionating column, means for heating light hydrocarbon oil and passing the heated oil into said column, means for cooling the upper por- '145 tion of said column, thereby supplying reflux therein, means for collecting and removing heavy reflux condensate from said column, a heating chamber into which said reflux condensate is discharged, means for collecting and means for supplying a plumbite-treated oil containing organic lead-sulfur compounds in solution to said means for heating said oil thereby precipitating lead sulfide, means for separating the precipitated lead sulfide from the heated oil products, a fractionating column, means for passing the heated oil into said column, cooling means in the upper portion of the column for supplying-reflux therein, means for withdrawing a heavy reflux condensate from the column, means for collecting and withdrawing unvaporized'oil from a lower point in the column, means for heating the withdrawn oil and for bringing it into indirect heat conductive contact with the reflux condensate to eflect removal or" lighter constituents from the latter, and means for subsequently returning the heated withdrawn oil to the column to supply heat therein.

20. In apparatus forthe treating and refining of low boiling hydrocarbon oils, a heating'means,

means for supplying an 011 containing organic lead-sulfur, compounds in solution to said heating means for heating the oil to decompose the organic lead-sulfur compounds to form insoluble lead sulfide and partially vaporize the oil, means for separating vapors resulting from said heating, means for removing the precipitated lead sulfide from the unvaporized oil, a fractionating column, means for discharging the separated vapors and the unvaporized oil into said column, cooling means in the upper por-- tion of the column for supplying reflux therein,

and means for supplying heat in the lower portion of said column. PHILIP L. KRAUEL. GEORGE 'W. WATTS. 

